Here's the primary difference between unions & lobbyists - lobbyists are held accountable for their actions. As a lobbyist you must produce results for the benefit of your client, else you will be replaced.
There really isn't an equivalent in unions. If the worker union you are a member of doesn't produce results to your benefit, your options to replace the union are virtually non-existent. And, I'd have to search around more than I care too, so take this as just my memory, I believe the large unions have helped make forming a new union incredibly difficult, so that if you want to unionize you are almost forced to join one of the large already established unions.
There really isn't an equivalent in unions. If the worker union you are a member of doesn't produce results to your benefit, your options to replace the union are virtually non-existent. And, I'd have to search around more than I care too, so take this as just my memory, I believe the large unions have helped make forming a new union incredibly difficult, so that if you want to unionize you are almost forced to join one of the large already established unions.